.338 Imperial Magnum History /RE-loading /dimensions

Gert Odendaal

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John P , member on our great forum request some information in regards to the scarce rifle caliber design by it`s originator Mr. Aubrey White residing in Canada. I am buying reamers/gauges/140 x scarce brass casings. I want to build/buy a aluminum chassis to use this caliber as a long distance shooting rifle for fun. Here are some documentation in regards to this great designed .338 Imperial Magnum ...other variants are known as .338 Edge ( Shaun Carlock designer) then derivatives like Remington Ultra Magnum versions, the Winchester Short Magnums are all designs derived from the Imperial Magnum design of Aubrey White `s company in Canada...
 

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  • Imperial Magnum Dimensions etc.pdf
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Gert Odendaal

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Did some reading about the Nosler caliber designs the past few years, very recent designs for sure. But not a new concept at all...the original concept was designed by a gunsmith in Canada. Aubrey White , who designed all these Imperial Magnum calibers on the 404 Jeffery parent case.

If Abrey White was successful in manufacturing and marketing these Imperial Magnum calibers the RUM, Edge and the WSM as well as these Nosler calibers designed very recently would never have seen the light of day...
 

crs

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Gert, Tho I never heard of the Imperial magnum, I somehow managed to get by with my .308, .338 WM, , .405, and .45.90.

I guess Mr. White was just too late for the market. + just too many new cartridges trying to crack the base of long established cartridges that can already take any animal extant.
Thanks for trying to educate this old shooter though.
 

Wyatt Smith

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When did the Imperial magnum come out.
I’m guessing it was not popular due to the powders available at that time. The 25-06 had a slow start due to the lack of slow burning powders available.
 

Gert Odendaal

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When did the Imperial magnum come out.
I’m guessing it was not popular due to the powders available at that time. The 25-06 had a slow start due to the lack of slow burning powders available.
Wyatt, I send Aubrey an email in this regards. Will give feedback in this regards.
 

Gert Odendaal

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Wyatt:
The genesis of the modem commercial beltless magnums is the story of the Imperial Magnum cartridge development. In 1989 Gus Rios, President of Royal Canadian Cartridge & Munitions Inc. (RCCM) of North Vancouver, B.C., purchased the "Imperial" and related Trademarks from Valcartier Industries Ltd. (IVI). These Trademarks had been purchased by IVI from the original Trademark holders, Canadian Industries Ltd. (CIL). CIL had been producing ammunition continuously in Canada since about 1919. RCCM intended to reintroduce a full line of Imperial brand ammunition to the International market place. To attract attention to the Imperial trademark they wished to develop a new, high performance, magnum rifle cartridge. RIOS had developed a cartridge he called the "Imperial .311 Canadian Magnum". This cartridge was the belted .338 Winchester case necked down to .311 caliber but did not provide the attention getting performance he was looking for. Aubrey White of Osoyoos, B.C. suggested that RCCM develop a full line of magnum cartridges, from 7mm to .358, all based on the non-belted .404 Jeffery case. It was anticipated that full length cartridges based on this case would be capable of out performing all existing belted magnums in their class. A .404 beltless case also provided additional benefits in that it allowed the maximum powder capacity possible in standard magnum rifle actions, ensured more accurate head spacing and improved feeding through rifle magazines. A non-beltled case is also less costly to produce than one with a belt. Even though White suggested other common calibers be given priority, Rios wanted the .311 caliber for a unique Canadian identity. White's company, North American Shooting Systems (NASS) designed and formed the cases, assembled some ammunition and a rifle for the .311.
 

Gert Odendaal

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The first test firing occurred on October 31st, 1989. By the next day, November 1 s t, load development resulted in record results. 180 gr. Sierra .311 bullets were consistently chronographed at 3,,435 fps within acceptable pressure limits, faster than any other in history. That performance was achieved with hand formed RWS .404 Jeffery cases, 89.0 grains of RL22 powder and #215 Federal primers in a 26" MacLennan barrel. It is still one of the very best loads for the .31L In 1990 NASS was licensed exclusively by RCCM to use the Imperial trademark to produce rifles. The cartridges were named "Imperial Magnum". RCCM was to produce cartridge cases and eventually load ammunition. Kimber of Oregon built one prototype rifle for NASS chambered for the .360 Imperial. Serial number of this rifle is NASS-OOO1. NASS intended to further contract Kimber to manufacture production rifles chambered for all the Imperial Magnums. Before production could begin, Kimber went into receivership. NASS continued cartridge development but marketing plans went on hold until 1991. To gauge dealer interest, RCCM publicly displayed the .311 magnum cartridges and a rifle for the first time in January of 1991 at the Dallas TX "Shot Show". Enthusiastic dealer response convinced RCCM to formally announce its intention to produce a full line of Imperial Magnum rifles and cartridges. Negotiations between RCCM and Aubrey White resulted in NASS developing the 7mm, .300, .311, .338 and .360 Imperial Magnum cartridges. RCCM and Aubrey White formed an RCCM subsidiary company call the "Imperial Magnum Corporation" (IMC). !MC was licensed to use the Imperial trademark to market Imperial Magnum cartridge cases and rifles. In 1993 Sako of Finland was subcontracted to produce barreled actions which were fitted with McMillan or Pacific Research stocks by !MC. Sako manufactured one prototype and one production run of 85 Imperial Magnum barreled actions .
 

Wyatt Smith

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Very interesting. Turns out my speculation was incorrect. Flashy advertising can cover up better products with worse ones sometimes.
 

Gert Odendaal

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he following are the Sako production figures of Imperial Magnum rifles; 7mm Imperial Magnum Serial No's IM 000001 to IM 000025 .300 Imperial Magnum Serial No's IM 100001 to IM 100015 .311 Imperial Magnum Serial No's IM 200001 to IM 200012 .338 Imperial Magnum Serial No's IM 300001 to IM 300013 .360 Imperial Magnum Serial No's IM 400001 to IM 400020 .360 Imperial Magnum Serial No. IM 000000 (Prototype) "Cavim" of Venezuela manufactured the cartridge cases using USA brass cups from Olin. IMC never produced loaded ammunition. Customers loaded their own using IMC cases, RCBS loading dies and loading data developed and supplied by IMC. IMC began marketing rifles and cartridge cases in 1993. Unfortunately a combination of subcontractor problems with the cartridge cases and financial difficulties experienced by a major shareholder forced IMC to cease operations in 1995. Customers were very pleased with both cartridge performance and rifles. Some complaints were received concerning soft brass cartridge cases but no rifle was ever returned for any reason. Many "Wildcat" cartridges have been hand formed from .404 brass over the years but the Imperial Magnums were the first with commercial cartridge cases and rifles. The large capacity beltless design has been an overwhelming commercial success but unfortunately not for the originators. Winchester and Remington have introduced at least eight new beltless magnums since !MC stopped production. Dakota Arms cartridges use only the beltless design and John Lazzeroni used the concept to develop his full line of rifles and cartridges. A total of thirty new non-belted magnum cartridges have been introduced to the market place. Only Weatherby continues to develop new cartridges with the outdated belted case. Aubrey G. White Box 306, Osoyoos, B.C. VOH 1VO Phone 250-495-3581 Fax 250-495-3131
 

Gert Odendaal

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Members, I am sure you all will agree that this is for sure a great story of a great caliber designed on the best developed case, the 404 Jeffery who seems to have a cult following on this forum..I think if counting the threads about the 404 Jeffery on this forum it might just be the most popular caliber ever discussed on this forum..the 404 Jeffery.

Aubrey White :rifle@telus.net

ritle@otvcablelan.net <ritle@otvcablelan.net>;

And now Nosler is duplicating the same concept...
 
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Ryan

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I learned about this caliber a couple years back because there was a rifle in it waa for sale in Soldotna, Alaska back then. My coworker listened to a community call-in sale radio program and a woman kept calling in trying to sell it there. Tough thing to sell in Alaska and especially the small communities on the Kenai Peninsula. I don't think she ever sold it, though she tried for quite a while. The name caught my attention because it wasn't the usual 338 Win Mag and I went digging. Interesting caliber.
 

Gert Odendaal

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Ryan, my interest in the .338 Imperial Magnum started way back when I bought a 404 Jeffery . The owner send me a box of original Kynoch rounds as well as as a mixed bunch of 404 Jeffery and .375 H&H Magnum rounds covered with corrosion .

At that stage I did not have new 404 Jeffery rounds or brass to do some re-loading . While showing my newest find to a gunsmith friend of mine , Johan Greying and mentioning that it would really be great if I can fire-form .375 H&H Magnum belted cases/brass to shoot in my 404 Jeffery .

I already had a .375 H&H Magnum Johan Greyling assisted me as a mentor to build it ( there is a thread about the build on the forum) He thought it to be a great idea and assisted me to fire -form the .375 H&H Magnum to fit into the 404 Jeffery .

I used these fire-formed 375-404 Jeffery brass for a long time shooting and hunting with it..until I was able to source new brass.

Then the idea to have other caliber with the parent case of the 404 Jeffery got hold of me..so I commenced searching for a caliber invented by only necking the 404 Jeffery brass up or down without any changes to the case dimensions .

So I found the Imperial Magnum story and Aubrey White after a few year`s research and reading .

I bought the .338 Imperial Magnum reamer/gauges and re-loading dies to build a fun shooting long range rifle , with a twist in the build....being my idea of casting from aluminum a MDT type of chassis for this barreled action ... :ROFLMAO: :ROFLMAO: (y) (y) While doing the research I found another parent case 404 Jeffery caliber :

the 9.3 x 70 DMW ....
 

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